PROJECT ABSTRACT More than 2,700 Illinois residents died of opiate overdose in 2017?a number that surpassed the state?s combined fatalities from road accidents and gun homicide. Individuals leaving jail and prison may be at highest risk of fatal overdose and other drug-related harms. Severely vulnerable men and women face these risks at precisely the moment they cross boundaries of fragmented criminal justice, social service, and public health systems, and are thus most vulnerable to lost follow-up and disengagement from services, or to have other basic needs left unattended. The challenge may be most acute for detainees who rapidly flow through jail settings, where unpredictable departures hinder discharge planning and care coordination, and where justice stakeholders may hold attitudes that stigmatize substance use or resistant to harm reduction interventions. Individuals returning to Chicago communities of color are near relatively rich resources for both treatment and harm reduction. Yet they must navigate epicenters of illicit narcotics distribution that feature particularly high incidence of fatal overdose from heroin, fentanyl, and other synthetic opioids. Rural individuals in Southern Illinois, may have long travel distances from any methadone facility or any DEA-waivered physician available to prescribe buprenorphine. Rural patients also face geographic barriers to the provision of naloxone and SSPs. Many harm reduction services have been designed and implemented to serve urban populations in traditional centers of opioid use. The acceptability and cultural competence of such rural services remains understudied. Our proposed multi-site ROMI trial (Reducing Opioid Mortality in Illinois) seeks to address this public health challenge through improved supports and service linkages to medication-assisted treatment (MAT), naloxone distribution, and syringe support services (SSPs) provided to justice-involved individuals living with opioid use disorders. We seek to test whether a unified case management approach that includes peer recovery coaches can improve treatment engagement and retention in five diverse urban and rural contexts that all experience high rates of opioid disorders, overdose, and related harms. We request funds to implement a five-site Randomized Controlled Trial, enrolling at least 1,000 individuals living with OUD. The ROMI trial will be carried out using a hub-and-spoke model, with centralized long- standing social services infrastructure at the Community Outreach Intervention Projects (COIP) hosted at the University of Illinois at Chicago (UIC). COIP provides case management/transition of care services to justice- involved opioid users, extending resources and technical assistance to less-populated rural areas hardest-hit by the opioid epidemic. Using a hybrid type-one effectiveness implementation design, we propose a simple but effective package of treatment and harm reduction interventions to reduce subsequent opioid use and related harms in diverse contexts. Our pragmatic trial is thus well-positioned to test effectiveness while collecting contextual data for implementation.